Effekten av metallhaltigt vatten på dagsländor (Ephemeroptera) i recipienter till aktiva och nedlagda gruvor i Norr- och Västerbotten

Sammanfattning

Metal pollution from Acid Mine Drainage (AMD) is one of the most serious environmental challenges associated with mining operations as well as a potential threat to biological life. Effects of AMD from mining regions are site-specific and depend on several biotic and abiotic factors in the recipient waters. The aim of this thesis was to assess the effects of metals (As, Cd, Cr, Cu, Ni, Pb, U, Zn) on mayfly (Ephemeroptera) larvae presence in recipient waters in Norr- and Västerbotten counties, Sweden. To fulfil this aim I used data from recipient surveys that has sampled benthic fauna with the kick-net method and collected water samples for chemical analysis. Regression analyses were performed to determine the relationships between dissolved and bioavailable concentrations of Cu, Ni, Pb and Zn. Additional regression analyses were performed to assess the relationships between the dissolved concentration of each metal and number of mayfly species as. Lastly, a regression analysis was performed for number of mayfly species and water pH. Results revealed that the number of mayfly taxa decreased exponentially as metal concentrations increased. There was also a correlation between number of mayfly taxa and pH, with the highest number of species in the pH interval 6,7 – 7,7. The ability to draw any definitive conclusions about the effects of metal pollution on mayflies in this geographical area are complicated by water pH, which for some sites is quite low. Further studies may be needed to determine how much of the effect can be attributed to high metal concentrations and how much is a consequence of low water pH.